Chemical Control
Different kinds of chemicals are used for device processing in the NFF (CWB) cleanroom. Some chemicals are dangerous when mixed with other chemicals or heated while others are dangerous on their own. NFF (CWB) users should have a good understanding of all the chemicals they intend to use. They should know what to do when accidents, such as chemical spills, occur. In general, safe chemical use can be achieved through proper training, proper labeling, proper storage and segregation, and proper transport. All chemicals used in the NFF (CWB) are controlled items. No chemicals can be brought in or taken out without permission. At HKUST, the Health, Safety and Environment Office (HSEO) also plays an important role in chemical safety. For more details, please visit http://www.ab.ust.hk/hseo/index.html.
A formal written notice must be given to NFF (CWB) management for approval if a chemical is to be taken out of the laboratory for use elsewhere. The notice must include a declaration of responsibility and liability in relation to safety and be signed by the project supervisor.
Table 1 - Standard Photoresists
| Item | Photoresist | Applications and Characteristics |
|---|---|---|
| PR-1 | HPR504 | g-line +ve PR, For normal thickness (1.0 ~ 1.5um) |
| PR-2 | HPR506 | g-line +ve PR, For thick film thickness (2 ~ 3um) |
| PR-3 | SPR660 | i-line +ve PR, For normal thickness (1.0 ~ 1.2um) |
| PR-4 | FH 6400L | g-line +ve PR, For normal thickness (1.0 ~ 1.2um) |
| PR-5 | AZ9260 | i-line +ve PR, For spray coating |
| PR-6 | AZ4620 | g-line +ve PR, For thick film thickness (~6um) |
| PR-7 | AZ4903 | g-line +ve PR, For thick film thickness (25 ~100um) |
| PR-8 | AZ5206E | 310-405nm dual-tone PR, For normal thickness (0.8 ~ 1.2um) |
| PR-9 | AZ5214E | 310-405nm dual-tone PR, For normal thickness (1.3 ~ 2um) |
| PR-10 | AZ7908 | i-line +ve PR, For normal thickness (0.6 ~ 0.8 um) |
Table 2 - Standard Developers
| Item | Developer | Applications and Characteristics |
|---|---|---|
| D-1 | FHD-5 | For PR-1 to PR-6; PR-8 to PR-10 |
| D-2 | AZ400K | For PR-7 |
Table 3 – Standard Organic Solvents
| Item | Organic Solvent | Applications and Characteristics |
|---|---|---|
| S-1 | MS2001 | +ve Photoresist stripper for PR1 to PR10 |
| S-2 | HMDS | Adhesion promoter for positive photoresist processing |
| S-3 | Acetone | Cleaning, and lift-off |
| S-4 | Isopropyl Alcohol (IPA) | Cleaning |
| S-5 | FH-ER | Back and front side rinsing |
| S-6 | MEK | For spray coating |
| S-7 | PGMEA | For spray coating and photoresist dilution |
Table 4 – Standard Acids
| Item | Acid | Applications and Characteristics |
|---|---|---|
| A-1 | Acetic Acid | For Aluminum etch |
| A-2 | Hydrochloric Acid (HCI) | For RCA2 and decontamination |
| A-3 | Phosphoric Acid | For Nitride removal and Aluminum etch |
| A-4 | Sulfuric Acid | For photoresist stripping, and piranha clean |
| A-5 | Nitric Acid | For Aluminum etch |
| A-6 | 777 Pad Etch | For etching Silicon Dioxide |
| A-7 | Freckle Etch | For Silicon residue removal |
| A-8 | CEP-200 | For Chrome etch |
| A-9 | Hydrofluoric Acid (HF) | For Oxide etch, and piranha cleaning |
| A-10 | Buffered Oxide Etchant BOE | For Oxide etch |
Table 5 – Standard Bases
| Item | Base | Applications and Characteristics |
|---|---|---|
| B-1 | Ammonium Hydroxide | For RCA1 |
| B-2 | Sodium Thiosulphate | For neutralization of Potassium Iodide (KI) solution |
| B-3 | Tetramethlammonium Hydroxide 25% (TMAH) | For Silicon etch (used at wetstation G and J only) |
Table 6 – Miscellaneous
| Item | Miscellaneous | Applications and Characteristics |
|---|---|---|
| M-1 | Hydrogen Peroxide (H2O2) | For cleaning and photoresist stripping |
| M-2 | Potassium Hydroxide (KOH) Pellet | For Silicon etch |
| M-3 | Potassium Iodide | For Gold etch etc. |
| M-4 | Iodine | For Gold etch |